On 12 Nov 2017, at 7:07, Ronald Wampler wrote:

Probably. IIRC, sometime the custom build system fails to copy of over
headers before they're needed […]

This should only happen when the target (that uses the headers) forget to declare them as a dependency¹.

I’ve corrected this in https://github.com/textmate/textmate/commit/75e8723e64c695e464dc78f5b9d84681b9b994da

¹ In the past there has been cases where a framework used only headers from another framework, but could not declare it a dependency because it would cause circular dependencies, I think we don’t have any of those ATM though.